1. Technical Field
The present disclosure relates to joint structures, and particularly, to a universal joint.
2. Description of Related Art
Generally, a common universal joint has only two degrees of freedom, and includes two transmission blocks and a cross axle connecting with the two transmission blocks. However, in some complicated and multi-degree-of-freedom mechanisms such as industrial robots, the multi-degree-of-freedom universal joints are needed to connect and control the robot arms to fulfill complicated movements or operations. Moreover, the common universal joint has a poor performance and the cross axle of the common universal joint is easily worn out in use.
Therefore, there is room for improvement in the art.